There are not many examples of previous cases where a user failed to get an IR signal so it is tricky to diagnose. There was a case though where somebody was trying to stream an unrectified IR feed with their R200 but it would not work. Intel support staff member David Lu advised that only enumerated streams could be set in combination.
Edit: I remembered another similar case where someone was only getting a black display for IR on Librealsense.
In that case, the suggestion for a fix was to do the patch (as you did) and afterwards using this line:
sudo modprobe uvcvideo.